You can use simple HTML tags to do standard formatting of the text in your headline.

Supported tags are:  

Line breaks - <br /> e.g. Break the line after this sentence. <br /> Another sentence here. 

Italics - <i> e.g. I want to <i>italicize</i> this word. 

Bold  - <b> e.g. The word <b>bold</b> is now bold. 

Underline -  <u> e.g.   <u>OfficialMe</u> is awesome.